This application claims the priority of French Application No. 99-08306 filed Jun. 7, 1999.
1. Field of the Invention
This invention relates to devices for data recording (and storage) in a severe environment. In a particular, but non-limiting example, it pertains to devices intended to equip airplanes; combat aircraft; ships; helicopters; combat vehicles, for example, armored vehicles; spacecraft; and similar equipment.
This invention relates to the storage and recording of all types of data, for example, numerical, audio and especially video data, and includes types of data that may appear in the future.
2. Background
In this general context, storage and recording on magnetic tape is included, but, in a preferred embodiment, data storage and recording is in a xe2x80x9ccartridge,xe2x80x9d that is to say, a hermetically sealed box, for example, a hard disk with its reading and recording device, comprising an xe2x80x9carmxe2x80x9d in the conventional fashion.
Hard disks, as used herein, include those that are currently available, especially disks with a format of 22xe2x80x3 or 32xe2x80x3, as usual, or any other hard disk or similar system that could appear in the future.
As persons skilled in the art will understand, the invention also applies to any other data storage and recording support that is contained in a box that must be hermetically sealed and that must be handled so as to be extracted from its housing after a given mission or operation and that must then be reinserted in that same housing for the next mission or operation.
Also included within the scope of such devices are semiconductor memories and any other technology having an equivalent, current or future function.
xe2x80x9cHermeticxe2x80x9d means here the vacuum-tight elements, that is to say, those that have a zero or extremely low leakage rate in a vacuum environment or under very low ambient pressure.
xe2x80x9cTightxe2x80x9d means watertight or humidity-tight elements.
In the above-mentioned environments, the equipment is typically subject to difficult or extreme conditions of vibration, vacuum (altitude) and/or shocks and similar constraints.
The most difficult problem to be solved is the problem of altitude and, the more or less forceful pressure drop to which the equipment will be subjected.
Pressure differences, when exerted on a non-hermetic device, will bring about incoming and outgoing flows of atmosphere in the box containing the data device and hence produce condensation phenomena. Moreover, in the case where the cartridge contains a hard disk, the arm will not remain at a predetermined distance from the disk, called the aerodynamic distance, but will risk being placed on the disk and scratching it, resulting in deteriorated recordings.
It is thus necessary to resort to hermetically sealed boxes and boxes that are generally xe2x80x9csuspended,xe2x80x9d that is to say, they are mounted on shock absorbers capable of reducing the shocks and vibrations undergone in the severe environments to acceptable values.
Data devices must also have a sufficient number of electrical contacts between the box (cartridge) and its support (receptacle) in the recorder to ensure the necessary transmissions of signals.
For example, according to the currently customary data processing standards, one must have about 50 contacts for the IDE standard and 80 for the SCSI standard.
However, recorders, especially those mounted in aircraft, must have as small dimensions as possible for obvious reasons of weight and bulk and, thus, the surface area available for contacts is reduced. This means that the contacts must themselves have small dimensions.
Another requirement is that contacts must, without any harmful wear and tear, withstand a large number of xe2x80x9cinsertions,xe2x80x9d that is to say, connection/disconnection cycles, without displaying any wear and tear that would induce parasite resistances that would affect the data. Military-type connectors, such as the SUB-D or HILC 38999 type, can withstand 200 to 400 insertions. The chip card connectors must withstand about 5,000 insertions.
It is also absolutely necessary that the cartridges be easily handled, that is to say, they must be easily extracted, transported and put back in place without any special precautions nor any special tools, even in a hostile or difficult environment. Thus, the boxes must be capable of being handled by technicians at airport runways, possibly with hands wearing thick gloves, and they must withstand shocks, such as those that result from being dropped, and similar trauma encountered in routine use.
The devices must therefore be compact, light, sturdy, hermetic, easily handled, and, obviously, reliable. They must present a large number of contacts on as small a surface as possibly and they must be capable of withstanding a large number of insertion cycles, for example, on the order of 3,000, without any damaging wear and tear. They must present an extraction and engagement mechanism that itself must be compact, simple, sturdy, reliable, and very precise, especially in terms of electrical contacts, that also must be easily handled, including with gloves. Insertion and extraction must not require any excessive force (entailing the risk of damaging the shock absorbers). The simple listing of these objectives underscores the difficulty of this undertaking because persons skilled in the art will understand that practically all of these criteria are antagonistic.
There is no currently available connector capable of meeting all of these criteria. The only connectors that come close to some of these parameters are connectors for memory cards, but they are infinitely too fragile and absolutely unsuitable for the environments contemplated for the invention.
Connectors called xe2x80x9chermetic lead-throughxe2x80x9d of the type shown in FIG. 1, are currently known.